Screen pipe



Jan: 3, 1 928 R. A. STEPS SCREEN PIPE Filed Sept. 30. 1925 INVENTOR Patented Jan. 3, 1928.

UNITED STATES".

I 1,654,618 PA E T OF IC ROBERT ALEXANDER 's'rnrs, or Los Auernnns, QALIFOBNIA.

SCREEN PIPE.

Original application filed March so, 1923, Serial 'No. 628,945. Divided and this application filed September so, 1925. Serial-No. 59,585. r

My present invention relates to an improved modification of the more general invention shown in my Patents Nos. 1,207,808 and 1,207 ,809, and this-present application is a division of my co-pending application Serial Number 628,945, filed March 30th,

1923, the latter covering'the-method hereinafter disclosed.

The object of the present invention is to produce screen pipessuch as are used in oil wells, water wells, etc., and to make such pipes with the combined benefits of increased screening capacity,-increased strength, and reduced production costs. V

It is understood that the screen' pipes to which this invention applies is used in oil or water Wells for the purpose of holding the sand a-ndgravel out, while the fluid passes through and'is pumped to the surface of the earth by proper pumps installed in the well. If the natural pressure on the fluid is sufficiently great the pump may of coursebe dispensed with as the fluid will then rise the well under its own pressure. Y

Screen pipes of this sort are made of heavy steel or iron pipe with suitable screening apertures formed therein. The pipe "comes in sections of various lengths,-often about 20 it. each, and from 4 to .16 inches in diam-' eter, and these sections are screwed together to give the required length of screen corresponding with the thickness of the strata in which the desired fluid is found.

' The'tendency of course is for the sand and gravel to come through the screen with the fluid, butth'is is undesirable for many reasons, and on this account care must be exercised in so forming the screening apertures that they hold back the sand efiectively with-.

out. retarding the .fiow of the liquid.

It is this result which my invention accomplishes very nicely. The screening apertures formed in accordance with my invention are narrower on the outside of the pipe than they are on the inside, so that the external sands are held out right at the outside surface of the pipe, but if any particles get past the narrow outside portion of the slot they pass right through the slot without sticking or clogging therein, as the slots which I produce are wider toward the inside than they are toward the outside of the pipe where the real excluding act-ion of the same is effected.

For the purpose of increasmg the screenarbor. 2 is a side view indicating the shape of the slotting saws diagrammatically. Fig. S-shows a way of carrying out the secend step in my invention 'wherebythe slots are formed so as to be narrower toward the outside of the pipe than they are at theinside of the pipe. Fig.4 is a sideview of the tool shown inFi'g. 3. Fig. 5 shows another way of carryin out the second step of my'invention, and Big. 6'is' a side view of the toolshown in Fig. 5. Fig. 7 shows a short-piece of the'screen pipe finished in accordancewith my invention, and Fig. 8*.is atransverse section of same.

By mounting the usual slotting saws 1- close together on the common arbor 2, Fig. 1, a pair of slots 3'may be cut in the wall of the piped, a bar 5 separating the slots in the pair. At the end of this first step in my method the side walls of the slots are substantially parallel, and the slots are as wide on the outside of the pipe as they are on the inside of the pipe. Figs. 3' ands show a roller 'G-adap'ted to bridge across the pair of slots, the edges 7 of therolgle'rbeing spaced sufliciently apart to rest ontheedges of'the slots which are "furthermost from each other. By any suitable means, this roller may be pressed down on the pipe at the same time'that it is rolled back and-forth along the length of the slots, and as this continues. these edges of the slots are pressed toward each other. 7 v p In practice I use a pneumatic or hydraulic cylinder for producing the required pressure on the roll, and in view of the concavity 10 termines the degree to which the lips are pressed toward each other, and 1t narrower slots are des red 1t is merely necessary to give the roller a few more strokes before the pressure 1s released.

At the end of this rolling operation the slots are seen to be narrower at the outside of the pipe than they are at'the'inside.

This gives the effective screening qualities which have already been described.

Figs. '5 and 6 show another tool ll'in the nature of a chisel, which may be used in place of roller 6. In this case the chisel may be struck with any sort of a hammer on the chisel head 12 and the opposite edges of the slot will thus be forced or pressed toward each other. V

After completing one pair of slots the operation is repeated as often as desired until the entire section of pipeis thus perforated. It is obviously important that the slots in each pair should be comparatively close together compared with the distance between neighboring pairs of slots, as this gives the increased screening area without correspondingly weakening the pipe. Also in the longitudinal spacing of the slots as shown in Figs. 7 and 8, where the length of the slot is disposed substantially parallel to the axis of the pipe, the screen is very strong in tensile strength because the transverse section of the pipe has been impairedto a minimurn, and the screen also is very strong against external compression strains because the grouping of the slots in pairs leaves the pipe with much larger uncut arches between the, slots than when the individual slots are equally spaced circumferentially around the pipe. Besides the screen pipe can be manufactured more economically when the slots are grouped in pairs in this way. I

In addition slots produced 1n my manner have the following 1 special characteristic;

As is noted from Figs. 3, 5 and 8, the walls of each slot are parallel with each other for a substantial distance starting at the :inside' surface of the pipe and passing outward through the slot toward the outs de surface of the pipe. Toward the outside of the pipe,v

however, the slot walls furthest from each other, in any pair of slots, are quite sharply inclinedtoward each other so as to givethe slot a pronounced taper immediately under sufaee V Signed at'Los Angeles in the county of the outside of the pipe where the influence of the pressure roll was felt. Such slots having all their taper concentrated near the outside of the pipe, instead of a slow, gradual taper from the same slot width at the outthe inside, have a. certain screening advantage as follows: In the usual slots which have onlya slow, gradual taper, a sand particle may squeeze through the mouth of the slot, and infinediately thereafter, sayfone quarter way through the slot,-inay roll on its axis and become bound or'jammed beside of the pipe to the same slot width at tween the slot walls, thereby creating a nucleus against which smaller particles .of sand can subsequently lodge to gradually clog the slot. Howeveryif the taper ofthe slot is pronounced as in my case, instead of only gradual, ,the likelihood of such a particle the slots in each pair being close together comparedwith the, distance between pairs.

andhaving a bar between the slots'in thev palr, the slot-walls furthermost from each other 111 any pair being p'arallelfwithregard:

toeach other towardithev inside of the pipe and inclinedtoward each other toward the, 7

outside of the pipe, and the slotwalls near-. est to each other in any pair being parallel:

toeach other throughout the thickness of the pipe so as to make the slots ,ofuniform width toward the inside of the pipe but with pronounced taper toward the outside in order to make the slots narrower toward the outside suface of the pipe than at the inside Los Angeles and State of California this 16th day of June, 1925. I

Rossini ALEXANDER. s rnrs. 

